The invention relates to a truck for a railroad car, or the like, and more particularly to the elastic connection between the railroad car, or the like, and the truck.
Various elastic connections between the body and the swivelable truck of a railroad car are known. These comprise steel coil springs and rubber thrust springs that are connected in series. See, for instance, German Provisional Pat. (Auslegeschrift) No. 23 13 887. These spring systems permit deflection and cause elastic restoration along three components of movement, namely the lifting motion of the truck as a result of vertical impacts, the transverse movement of the truck in the case of lateral impacts, and the expected rotary movement of the swivelable truck with respect to the car body on curves in the track.
Known series connected spring systems have various defects. The different spring elements are arranged one above the other. This produces a large structural height for the spring system and thus frequently requires that a costly offset be constructed in the frame of the swivel truck and/or that corresponding recesses be formed in the bottom of the car body. This either reduces the strength of the structural parts or increases their weight. Another disadvantage is that there is a high stress on the coil springs with the danger of instability of the spring system, especially if there is a relatively large horizontal spring movement with only a moderate restoring force available from the spring system.